The present invention relates to an air spring and a bogie.
An air spring making use of elasticity of compressed air has conventionally been known. For example, Japanese Patent Laying-Open No. 2000-035075 describes one example of a conventional air spring. The air spring described in this document has a height control mechanism for keeping an amount of compressive deformation (compression stroke) substantially constant.
Japanese Patent Laying-Open No. 2012-017769 also describes another example of a conventional air spring. The air spring described in this publication is an air spring with a stopper including downward-movement restriction means. Japanese Patent Laying-Open No. 2012-145135 describes yet another example of a conventional air spring. This air spring includes a stopper for restricting an amount of displacement in an up-down direction.
An air spring according to one manner of the present invention includes an outer cylindrical member, an inner cylindrical member, a diaphragm, a stopper assembly, a pivoting mechanism, and a space portion. The inner cylindrical member is combined with the outer cylindrical member. The diaphragm couples the outer cylindrical member and the inner cylindrical member to each other and provides an internal space between the outer cylindrical member and the inner cylindrical member. The stopper assembly is arranged in the internal space as being pivotable over the inner cylindrical member and can suppress movement of the outer cylindrical member toward the inner cylindrical member more than necessary. The pivoting mechanism pivots the stopper assembly over the inner cylindrical member. The space portion is provided in the internal space between the stopper assembly and the inner cylindrical member, and can lower a resistance in pivot of the stopper assembly.
An air spring in an embodiment of the present invention will be explained below with reference to
Initially, the air spring described in PTD 1 will be explained. In this air spring, a stopper (8) can rotationally be operated around a shaft portion (2a) of a lower plate (2). As shown in FIG. 1 of PTD 1, however, the entire bottom surface of a base (8a) of the stopper (8) is in contact with a flat surface of an inner cylindrical member (4) and hence an area of contact therebetween is great. Therefore, a sliding resistance in rotational operation of the stopper (8) is high. In particular, since the stopper (8) is arranged in a hermetically sealed space in the air spring described in PTD 1, a pressure in the hermetically sealed space is applied to the stopper (8) and the sliding resistance further increases.
The air spring described in PTD 2 includes a lower stop member (12). This lower stop member (12) can move from a first stopper position (a stand-by position) shown in FIG. 2 (a) of PTD 2 to a second stopper position (a raised position) shown in FIG. 2 (b). In this air spring, a slide plate (20) is interposed between an upper plate portion (2A) and each lower stop member (12) such that each lower stop member (12) smoothly moves, however, the slide plate (20) comes in contact with substantially the entire surface of both of the upper plate portion (2A) and each lower stop member (12). Therefore, as in PTD 1, an area of contact is again great. In addition, since a pressure in the hermetically sealed space is applied, a sliding resistance in pivot of the lower stop member (12) is high as in PTD 1.
The air spring described in PTD 3 includes a lower stopper (16). A movable body (7) of this lower stopper (16) can rotationally be operated around a central axis (18). In a rotational operation of the movable body (7), a taper (32) of the movable body (7) and a taper (41) of a holding body (8) slide with respect to each other. Therefore, as in PTDs 1 and 2, an area of contact between the movable body (7) and the holding body (8) is again great. Additionally, a pressure in the hermetically sealed space is applied. Therefore, as in PTDs 1 and 2, a sliding resistance in a rotational operation of the movable body (7) is high.
The air spring in the present embodiment can solve the problems of the air springs described in PTDs 1 to 3 as above. The air spring in the present embodiment can be used in various applications such as a suspension, a vibration isolator, and a vehicle height controller. When the air spring is employed in railway vehicles, it is attached between a vehicle and a bogie unit (a bogie and wheels) and vibration transmitted from the wheels to the vehicle can be mitigated.
The air spring in the present embodiment is a self-sealing air spring, and includes an outer cylindrical member, an inner cylindrical member combined with the outer cylindrical member, and a diaphragm coupling the outer cylindrical member and the inner cylindrical member to each other and providing an internal space between the outer cylindrical member and the inner cylindrical member. The outer cylindrical member and the inner cylindrical member can be made of a rigid material such as a metal or fiberglass reinforced plastics. The diaphragm can be made of an elastic material such as rubber and elastomer. The internal space is hermetically sealed and pressurized air is sealed in the internal space.
The air spring in the present embodiment also includes a stopper assembly arranged in the internal space as being pivotable over the inner cylindrical member, the stopper assembly allowing suppression of movement of the outer cylindrical member toward the inner cylindrical member more than necessary, and a pivoting mechanism pivoting the stopper assembly over the inner cylindrical member. The stopper assembly may be driven manually or with motive power from a motive power source. In the air spring in the present embodiment, an area of contact between the stopper assembly and the inner cylindrical member is decreased. Thus, a mechanical resistance between the stopper assembly and the inner cylindrical member in pivoting the stopper assembly can be lowered and a sliding resistance therebetween can be lowered. For decreasing an area of contact between the stopper assembly and the inner cylindrical member, in the present embodiment, a space portion is provided between the stopper assembly and the inner cylindrical member so as to decrease an area of contact between the stopper assembly and the inner cylindrical member.
Embodiments of the invention of the present application will initially be listed and described.
(1) An air spring 10 according to one manner of the present invention includes an outer cylindrical member 1, an inner cylindrical member 9, a diaphragm 4, a stopper assembly 2, a pivoting mechanism 5, and a space portion 3. Inner cylindrical member 9 is combined with outer cylindrical member 1. Diaphragm 4 couples outer cylindrical member 1 and inner cylindrical member 9 to each other and provides an internal space 27 between outer cylindrical member 1 and inner cylindrical member 9. Stopper assembly 2 is arranged in internal space 27 as being pivotable over inner cylindrical member 9 and can suppress movement of outer cylindrical member 1 toward inner cylindrical member 9 more than necessary. Pivoting mechanism 5 pivots stopper assembly 2 over inner cylindrical member 9. Space portion 3 is provided between stopper assembly 2 and inner cylindrical member 9 and can lower a resistance in pivot of stopper assembly 2. Thus, difficulty in pivot of stopper assembly 2 by being pressed against inner cylindrical member 9 by a pressure in internal space 27 can be suppressed.
(2) Air spring 10 according to (1) may include a communication path 31 allowing communication between space portion 3 and internal space 27.
(3) In air spring 10 according to (1) or (2), stopper assembly 2 may be arranged on a surface of inner cylindrical member 9. Stopper assembly 2 may have a stopper portion 21 which can suppress movement of outer cylindrical member 1 and a base portion 22 carrying stopper portion 21. Space portion 3 may be provided between base portion 22 and the surface of inner cylindrical member 9.
(4) In air spring 10 according to (3), a recess portion 31 may be provided in at least one of a surface in base portion 22 located on a side of the inner cylindrical member and the surface of inner cylindrical member 9. Space portion 3 may be defined by at least a part of recess portion 31.
(5) In air spring 10 according to (3), a projection portion 29 may be provided on at least one of a surface in base portion 22 located on a side of the inner cylindrical member and the surface of inner cylindrical member 9. Projection portion 29 may define space portion 3 between base portion 22 and inner cylindrical member 9.
(6) In air spring 10 according to (5), at least a tip end portion of projection portion 29 may be composed of a material allowing a coefficient of friction between projection portion 29 and base portion 22 or inner cylindrical member 9 to be smaller than a coefficient of friction between base portion 22 and inner cylindrical member 9.
(7) In air spring 10 according to (1) or (2), the space portion may be provided by arranging an antifriction material 34 between stopper assembly 2 and inner cylindrical member 9.
(8) In air spring 10 according to (1), in the internal space, stopper assembly 2 may include an internal chamber 15 separate from internal space 27. Internal space 27 and internal chamber 15 may communicate with each other through space portion 3.
(9) In air spring 10 according to (1), stopper assembly 2 may have stopper portion 21 which can suppress movement of outer cylindrical member 1 and base portion 22 carrying stopper portion 21. Stopper portion 21 may contain internal chamber 15. A communication hole 20 allowing communication between the internal chamber and the space portion may be provided in base portion 22.
(10) A bogie according to one manner of the present disclosure includes the air spring according to any of (1) to (9). Thus, even when vibration is applied in a direction perpendicular to a direction from the outer cylindrical member to the inner cylindrical member, break of the air spring can be suppressed.
Details of the embodiments of the invention of the present application will now be described.
As shown in
As shown in
A bottom plate 8 is arranged under inner cylindrical member 9. Bottom plate 8 has a cylindrical portion in its central portion and the cylindrical portion is inserted in ring portion 23 of stopper assembly 2. A screw hole 33 is provided in inner cylindrical member 9, and bottom plate 8 can be fixed to inner cylindrical member 9 by screwing a bolt 28 inserted into bottom plate 8 into screw hole 33. A lever 5 for pivotally operating stopper assembly 2 is disposed between inner cylindrical member 9 and bottom plate 8. One end of lever 5 is fixed to ring portion 23 by a screw 25. A handle may be attached to the other end of lever 5 such that lever 5 can pivotally be operated with a hand. The other end of lever 5 is located outside bottom plate 8. Laminated rubber 6 is arranged under bottom plate 8.
Three base portions 22 are simultaneously pivoted by pivotally operating lever 5 and accordingly three stopper portions 21 are also simultaneously pivoted. Three base portions 22 slide over the upper surface portion of lower plate 19 of inner cylindrical member 9. By providing a plurality of groove portions 31 in the upper surface portion, a space portion can be provided under base portion 22. Thus, an area of contact between the upper surface portion of lower plate 19 of inner cylindrical member 9 and base portion 22 can be decreased. Consequently, a sliding resistance between the upper surface portion of lower plate 19 of inner cylindrical member 9 and base portion 22 can be lowered. In particular, when a plurality of base portions 22 are provided, an effect to lower a sliding resistance is noticeable.
As shown in
As shown in
Though internal space 27 and internal chamber 15 communicate with each other through space portion 3 in the example shown in
A second embodiment of the present invention will now be described with reference to
As shown in
The construction other than the above is the same as in the first embodiment. Groove portion 31 can be provided in the upper surface portion of lower plate 19 of inner cylindrical member 9 also in the present second embodiment as in the first embodiment. A groove portion should only be provided in at least one of base portion 22 and the upper surface portion of lower plate 19 of inner cylindrical member 9.
A third embodiment of the present invention will now be described with reference to
As shown in
In the example in
Space portion 3 may be provided under base portion 22 by providing a projection portion on a side of the upper surface portion of lower plate 19 of inner cylindrical member 9. Furthermore, a projection portion may be provided in both of base portion 22 and the upper surface portion of the lower plate.
At least the tip end portion of the projection portion is preferably composed of a material allowing a coefficient of friction between the projection portion and base portion 22 or the upper surface portion of the lower plate of inner cylindrical member 9 to be smaller than a coefficient of friction between base portion 22 and the upper surface portion of lower plate 19 of inner cylindrical member 9. Thus, a sliding resistance between the upper surface portion of lower plate 19 of inner cylindrical member 9 and base portion 22 can further be lowered. Examples of a material which can lower a coefficient of friction include a resin such as polytetrafluoroethylene (PTFE).
A fourth embodiment of the present invention will now be described with reference to
As shown in
In the example in
Antifriction material 34 may be attached to the lower surface of base portion 22 or to both of the lower surface of base portion 22 and the upper surface portion of the lower plate of inner cylindrical member 9. When antifriction material 34 is attached to the lower surface of base portion 22, a recess portion which can receive antifriction material 34 is preferably provided in the lower surface of base portion 22.
A construction of a bogie according to a fifth embodiment will be described below.
An effect of the bogie according to the fifth embodiment will be described below
As set forth above, the bogie according to the fifth embodiment has air spring 10 according to any of the first to fourth embodiments. Therefore, according to the bogie in the fifth embodiment, break of air spring 10 can be suppressed even when vibration is applied to a direction perpendicular to the direction from outer cylindrical member 1 toward inner cylindrical member 2.
Though the embodiments of the present invention have been described as above, combination of features in each embodiment as appropriate is also originally intended. It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
1 outer cylindrical member; 2 stopper assembly; 3 space portion; 4 diaphragm; 5 lever (pivoting mechanism); 6 laminated rubber; 8 bottom plate; 9 inner cylindrical member; 10 air spring; 11, 12, 13, 14 protrusion portion; 15 internal chamber; 16 ring-shaped projection portion; 17 coupling portion; 18 flange portion; 19 lower plate; 20 communication hole; 21 stopper portion; 22 base portion; 23 ring portion; 24 hole portion; 25 screw; 26 rubber seat; 27 internal space; 28 bolt; 29 projection portion; 30, 31 groove portion; 32 plunger; 33 screw hole; 34 antifriction material; 35 welded portion; 36 recess portion; 37 upper plate; 37a flat plate portion; 37b sidewall portion; 38 through hole; 81 bogie frame; 82 axle; and 83 wheel.
Filing Document | Filing Date | Country | Kind |
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PCT/JP2016/080696 | 10/17/2016 | WO | 00 |